INTRODUCTION

• Liquid Composite Molding (LCM): Thermoset resin injected into the mold filled with fiber preform under pressure difference.
• Multiple injection gates are designed in the mold to reduce fill time.
• Mold fill time is sensitive to the location of the gates

EXHAUSTIVE SEARCH FOR OPTIMAL MULTIPLE GATE INJECTION PLAN IS IMPRACTICAL

• Gate locations have to be optimized to yield shortest fill time.
• Finite Element software LIMS is developed to predict fill time for each possible multiple gate combination scenario
• Number of simulations grow at factorial speed with increasing number of gates which renders the exhaustive search challenging for multiple gate location optimization problem.

APPROACH TO OPTIMIZATION

• Mold filling simulation returns not only the time needed to fill the part, but also fill time for each node on the mold surface.
• The contour of the fill time for each node consists of the mold filling history, and the surfaces are separated into regions along the weld line(s). Regions separated are defined as Voronoi Tessellation of the surface.

CASE STUDIES

SUMMARY AND CONCLUSIONS

• Multiple gate location optimization with fill time as the objective function is recast into searching for the optimal tessellation of the mold part surface with a objective fill time function defined.
• A fast iterative algorithm is used to find the optimal solution: CVT of the mold part surface.
• CVT result provides the optimal gate configuration that yields the shortest fill time.

ACKNOWLEDGEMENTS

This work is supported by the Defense Advanced Research Projects Agency (DARPA) through the Composite Orthotics program.